@mikeraynham could you tell us how large your data is in a pure and/or compacted form. Have you tried the new Columnar storage settings with the nodes (KNIME Columnar Table Backend Boosts Performance | KNIME)?
You could check out further options to speed up things with your data. And you might want to think about giving your KNIME more RAM, like 12 GB or so. But this very much might depend on the overall size of your data and what else is going on.
Maybe you could provide such a workflow with the instructions to create a sample file where you experienced this problem.